The Core Laboratory of the Marian Anderson Comprehensive Sickle Cell Center will serve as the nucleus for clinical diagnostic issues of the center and will play a pivotal role in facilitating the day-to-day management and procurement of samples for all research protocols. Select research assays will be performed in the Core. The core will assume the responsibility of providing diagnostic tests and counseling for patients followed at our center. While some of the resources will be static, that is, these resources are fully developed and can be utilized by any portion of the center or other centers, there will also be a dynamic component focusing on development of new tools as well as revisions of current techniques. Since a unique interest of the center is related to the dramatic changes in hemoglobin expression that occur during the neonatal period and first several years of life in sickle cell disease, a significant dynamic component of the core involves the measurement of fetal hemoglobin expression. Specifically, the Core Laboratory will have these objectives: I. Studies related to Hemoglobinopathy Diagnosis. II. Studies related to the Research Projects of the Center (i) Modify and refine current methods of hemoglobin characterization focusing on fetal hemoglobin. (ii) Provide analysis of various red cell characteristics (iii) Examine the polymerization potential in relation to the post-natal decline in fetal hemoglobin production III. Enhance the day-to-day mechanics of the clinically based research projects of the Center.